The test for islet cell cytoplasmic antibodies (ICA) is a good predictor of individuals at risk to develop Type I diabetes, and thus has potential value in identifying candidates for future measures aimed at preventing the disease. However, problems with standardization limit the reliability of the ICA assay. The goal of this project is to make available a standardized, and hence more reliable system for detecting ICA. Specific objectives are to: 1) establish a protocol for procuring donor pancreas that results in optimal reactivity and retention of tissue morphology; 2) establish the most sensitive and reproducible fluorescent indicator system for visualizing the ICA reaction; 3) maximize the stability of islet cell antigens in tissue sections; and 4) develop a separate parallel system that allows the user to assess his skills in performing, reading and interpreting the ICA test. These aims will be addressed by: 1) documenting time limits for tissue processing beyond which reactivity and histology deteriorate and examining pancreas perfusion as a means of extending these time limits; 2) comparing five fluorescent indicators for specificity, sensitivity and reproducibility in the ICA assay; 3) comparing shelf-lives of pancreas sections after various modes of fixation; and 4) developing the components of a user standardization kit. This research will lay the groundwork for Phase II development of a commercially marketable ICA assay package.